my social media wont let me sign up even though I downloaded the apps

I downloaded Snapchat,Instagram and TikTok and the instagram one would not load the page and for snap chat there is an error where once I entered my password it would say there was an error code C16A and TikTok I would enter my birthday and it would not load to the next page. I don’t have very good internet but I do have internet I can live with and I have the iPhone XS so I don’t know if it’s the phone or something else. Also my phone is up to date with the software updates. IM STUCK HELP ME OUT PLEASE